Switching regulator is a vitally important device. Switching regulators are building blocks used extensively in power systems, industry, motor, communication, networks, digital systems, consumer electronics, computers, and any other fields that require high efficient voltage regulating functions.
Switching regulators (i.e., DC-TO-DC converters) can provide output voltages which can be less than, greater than, or of opposite polarity to the input voltage. Prior Art FIG. 1 illustrates a basic architecture of a conventional switching regulator 100. The conventional switching regulator 100 basically consists of an oscillator, a reference circuit 102, an error amplifier, a modulator including a comparator, resistors, and a control logic circuit. Control technique of switching regulators has typically used two modulators: a pulse-width modulator and a pulse-frequency modulator. The output DC level is sensed through the feedback loop including two resistors. An error amplifier compares two input voltages: the sampled output voltage and the reference voltage. The output of the error amplifier is compared against a periodic ramp generated by the saw tooth oscillator. The pulse-width modulator output passes through the control logic to the power switch. The feedback system regulates the current transfer to maintain a constant output voltage within the load limits. In other words, it insures that the output voltage level reaches the equilibrium. When the output voltage level reaches the equilibrium, VF is equal to VREF, as shown in Prior Art FIG. 1.
However, it takes a vast amount of time until the output voltage level reaches the equilibrium from an initial condition after the switching regulator of Prior Art FIG. 1 starts. Therefore, power and time are consumed until the switching regulator's output voltage level reaches the equilibrium. In addition, it takes a long time to simulate and verify the conventional switching regulator 100 before fabrication since its simulation time is absolutely proportional to time that is required the switching regulator's output voltage level to reach the equilibrium. Hence, this long simulation adds additional cost and serious bottleneck to design time-to-market. In other words, the slow start-up of the switching regulator increases design simulation time. For these reasons, the conventional switching regulator 100 of Prior Art FIG. 1 is very inefficient to implement in system-on-chip (SOC) or integrated circuit (IC).
Thus, what is needed is a fast starting-up switching regulator that can be highly efficiently implemented with a drastic improvement in a very fast start-up time, start-up time controllability, performance, time-to-market, power consumption, power and time management, efficiency, cost, and design time. It is highly desirable to enable all of the switching regulators' output voltage levels to reach the equilibrium immediately for much higher power efficiency or according to schedule. The present invention satisfies these needs by providing five embodiments.